Dynamically turning off interactions in a two-component condensate

We propose a mechanism to change the interaction strengths of a two-component condensate. It is shown that the application of $\pi /2\mathrm{}$ pulses allows us to alter the effective interspecies-interaction strength as well as the effective interaction strength between particles of the same kind. This mechanism provides a simple method to transform spatially stable condensates into unstable ones and vice versa. It also provides a means to store a squeezed spin state by turning off the interaction for the internal states and thus allows to gain control over many-body entangled states.